Zusammenfassung

The "Nanoarchaeota" are a novel archaeal phylum, forming a unique, deep branch in the 16S rRNA based phylogenetic tree of life. "Nanoarchaeum equitans", the first cultivated representative, is a hyperthermophilic, anaerobic nano-sized coccus with a genome size of about 490 kb. Growth occurs only in coculture with a new chemolithoautotrophic Ignicoccus species.